That Reptile Blog » Land Crabshttp://blogs.thatpetplace.com/thatreptileblog
- Reptile, Amphibian and Exotic Pet Care and InformationTue, 14 Jul 2015 13:53:48 +0000en-UShourly1http://wordpress.org/?v=4.2.3Vampire Crab Care: 2 New Land Crab Species Found Among Pet Trade Animalshttp://blogs.thatpetplace.com/thatreptileblog/2015/03/24/vampire-crab-care-2-new-land-crab-species-found-among-pet-trade-animals/
http://blogs.thatpetplace.com/thatreptileblog/2015/03/24/vampire-crab-care-2-new-land-crab-species-found-among-pet-trade-animals/#commentsTue, 24 Mar 2015 20:51:56 +0000http://blogs.thatpetplace.com/thatreptileblog/?p=5444Various land crabs have long been available in the pet trade, but despite their brilliant colors and fascinating behaviors, few have caught on among terrarium keepers here in the USA. This changed a bit when several spectacularly-colored species, usually sold as Vampire Crabs or Red Devils, began showing up in the early 2000’s. Recent investigations ...

Various land crabs have long been available in the pet trade, but despite their brilliant colors and fascinating behaviors, few have caught on among terrarium keepers here in the USA. This changed a bit when several spectacularly-colored species, usually sold as Vampire Crabs or Red Devils, began showing up in the early 2000’s. Recent investigations into the natural history of these crabs resulted in the surprising finding that two species new to science have been kept and bred by hobbyists for at least 10 years!

Uploaded to Wikipedia Commons by (Bhny)

Crabs at the Bronx Zoo

I had long urged my bosses at the Bronx Zoo to pay more attention to terrestrial crabs, especially as many do so well in large planted exhibits. I was given some latitude, and happily established colonies of “Halloween Crabs” (please see photo), “Soap Box Crabs”, various members of the family Potomonidae and Land Hermit Crabs throughout the reptile house. We even kept the massive Coconut Crab for a (too brief!) period. But the time and money needed to study them properly never materialized, and I still wonder at the identity of some that passed my way. So I was quite happy to see that interest which germinated in the pet trade has resulted in an important discovery.

The New Species

According to a recent article in the journal Raffles Bulletin of Zoology (V. 63:3-13; 1/2015) two previously undescribed species have been found among pet trade animals commonly sold as Vampire Crabs. They were collected on Java, and have been named Geosesarma hagen and G. dennerle. Individuals vary in coloration, but in general they are bright orange and deep purple with cream blotches, respectively. Others I’ve kept, which exhibited similar lifestyles, sported shocking yellow eyes, brilliant red claws, and jet black carapace borders.

Uploaded to Wikipedia Commons by russavia

Land Crab Diversity

As crab enthusiasts know, Indonesia’s many islands, as well as others in the Indian and South Pacific Oceans, support a fantastic array of terrestrial (and marine) crabs. From the unbelievably-large Coconut Crab to the spectacular migrations of Christmas Island’s Red Crabs (please see photos), the region’s crab diversity is unmatched anywhere on earth. Some small islands support a dozen or more species, which seem to fill niches taken elsewhere by reptiles, amphibians and small mammals (or monkeys, perhaps, in the Coconut Crab’s case!).

As seems to be true for the newly-described Vampire Crabs, many have long been isolated from relatives, so new species almost certainly remain to be found.

Vampire Crab Terrariums

Vampire Crabs and their relatives do best in moist, well-planted terrariums that allow climbing and burrowing opportunities. Live carpet moss and leaf litter over a topsoil/coconut husk substrate suits them well. Philodendron, Chinese Evergreen, Pothos, Cast Iron Plants and other sturdy species will add immensely to their quality of life and your enjoyment of them. Although only a mere 0.8-1.3 inches in length, these active little fellows will do best if given plenty of room.

Uploaded to Wikipedia Commons by Jitka Erbenov

Although said to be nocturnal in the wild, most that I’ve kept were eager to forage by day once they settled in, especially if ample cover was provided. A temperature gradient of 75-85 F, and an ambient humidity level of 70% or higher should be established. Terrarium heat pads attached to the tank’s sides and red light bulbs will assist you in heating and observing your pets after dark.

Diet

Most terrestrial crabs feed opportunistically on almost any organic material that comes along. However, Vampire Crabs seem more inclined to seek and chase down live prey than do many others – so much so, in fact, that they remind me of that most voracious of inshore predators, the Blue Claw Crab!

As we do not know their exact nutritional requirements, I provide a highly-varied diet for all terrestrial crabs. Vampires will readily accept Zoo Med Hermit Crab Food and many other diets formulated for terrestrial hermit crabs, freeze dried shrimp, frozen and flake foods marketed for tropical fishes, moist algae tablets and turtle chow, small live and dead crickets, black worms and other invertebrates, and some fruits and vegetables. Calcium blocks will be used by some species, and powdered calcium should be mixed into their food as well.

I especially like to offer fresh leaf litter and grass clippings – all land crabs, including the popular Terrestrial Hermit Crabs, will eagerly pick through this material for small invertebrates, plant shoots, moss, lichen, decaying leaves and other tidbits that likely provide important nutrients.

A shallow bowl of de-chlorinated water should always be available for soaking and breeding purposes (please see below).

Some keepers report that Vampire Crabs are less inclined than others to hunt down and consume their molting tank mates (they are defenseless until the new exoskeleton hardens). I, however, have no faith in crab “sociability”, and so advise you to include deep substrate and many hiding places…along with lots of food!

Breeding

Unlike Coconut, Hermit and Fiddler Crabs, all of which require marine water for soaking and as a breeding site, Vampire Crabs have cut all ties with the ocean. Females carry their 20-50+ eggs about until they hatch or are ready to hatch, whereupon they are deposited in shallow pools of fresh water.

Crab enthusiasts will be especially happy to learn that Vampires have thoughtfully done away with the planktonic larvae that have long prevented us from breeding others in captivity. Instead, tiny, fully formed crabs (crablets?) emerge from the eggs. They are said to chase down fruit flies and springtails in adult fashion; related species under my care have accepted other typical crab foods as well.

]]>http://blogs.thatpetplace.com/thatreptileblog/2015/03/24/vampire-crab-care-2-new-land-crab-species-found-among-pet-trade-animals/feed/0Best Substrate for Hermit Crabs – Avoid Deadly Mistakeshttp://blogs.thatpetplace.com/thatreptileblog/2014/02/10/best-substrate-hermit-crabs-avoid-deadly-mistakes/
http://blogs.thatpetplace.com/thatreptileblog/2014/02/10/best-substrate-hermit-crabs-avoid-deadly-mistakes/#commentsMon, 10 Feb 2014 21:55:01 +0000http://blogs.thatpetplace.com/thatreptileblog/?p=4240 I’ve had the good fortune of working with many species of terrestrial Hermit Crabs, including the unbelievably huge Coconut Crab (Birgus latro). Most are surprisingly long-lived – for example, the species most commonly sold in pet stores (the Caribbean Hermit Crab, Coenobita clypeatus) can survive for 20 or more years if properly cared for! ...

I’ve had the good fortune of working with many species of terrestrial Hermit Crabs, including the unbelievably huge Coconut Crab (Birgus latro). Most are surprisingly long-lived – for example, the species most commonly sold in pet stores (the Caribbean Hermit Crab, Coenobita clypeatus) can survive for 20 or more years if properly cared for! We’ve learned a great deal about Hermit Crab captive needs over the years, but serious mistakes are still commonly made when it comes to hermit crab substrate choice. The ability to successfully molt and form a new exoskeleton, and to survive the attacks of cage-mates during this dangerous time, hinges upon the substrate. Even if all else is perfect, Hermit Crabs will expire long before “their time is due” if they do not have access to appropriate substrates of the correct depth.The Dangers of Molting

As Hermit Crabs grow, they molt or shed their exoskeleton (the body’s hard, external covering) and replace it with a larger one. The old exoskeleton, an important source of calcium and other minerals, is consumed. After molting, crabs are soft and unable to move for varying lengths of time. Predators of all types consider these moist, defenseless crabs as the ultimate in gourmet meals. The scents released by molting crabs are nothing short of a dinner bell to other crabs…including cage-mates with whom they have peacefully co-existed for years!

Prior to molting, Hermit Crabs burrow into the soil or sand. In natural habitats, this most likely helps to lessen telltale scents and to physically conceal them from predators. The strategy also works well in captivity, although in close quarters some molters may be found and consumed.

The Ideal Type and Depth of Hermit Crab Substrate

Even the smallest of Hermit Crabs should be provided with at least 6 inches of moist substrate. Hermit Crabs of ping-pong ball size should be kept on 8 inches of substrate, and the depth should be increased accordingly for larger animals. This differs radically from how most are displayed in stores, I know, and represents a real disservice to customers (and, of course, crabs!).

An equal mix of Zoo Med Hermit Crab Sand and Coconut Fiber is ideal for Caribbean Hermit Crabs (Coenobita clypeatus), Ecuadorian Hermit Crabs (Coenobita compressus) and the several Asian species that commonly appear in the pet trade. The mixture holds together well, supports burrows, and is easy for the crabs to manipulate. I also favor the Hermit Crab Sand because it is fortified with calcium, which will be consumed by your pets, especially just prior to molting (please also see “Nutrition”, below).

If you keep the substrate slightly moist – wet enough so that it barely clumps together when squeezed by hand –your crabs will be able to dig down when necessary. They will also enjoy sorting through the soil/sand mix in search of food. You can encourage them to become more active by burying Hermit Crab pellets and other treats just below the surface.

Uploaded to Wikipedia Commons by Michael Quigley

Time Spent Below-Ground

When I first began keeping Coconut Crabs at the Bronx Zoo in the early 1980’s, we didn’t realize just how long molting crabs needed to remain below-ground – up to 6 months for those behemoths! Today, many crab enthusiasts are surprised to learn that the average “pet-sized” Hermit Crabs remain buried for at least 2 weeks – and often up to 1 month – when molting. Well-meaning owners who do provide deep substrate sometimes dig-up their pets out of concern – this always ends badly! Medium to large Hermit Crabs may remain underground for 2-3 months when molting.

Nutrition and Molting

Hermit Crabs must consume calcium-rich foods and calcium supplements in order to produce strong exoskeletons. A variety of salts are also used in the shedding process, to help split the old exoskeleton (please post below for details); access to salt water appears critical to their long term health. Please see this article and check out these Hermit Crab Care Supplies for further information, and be sure to post your questions and observations below.

Hermit Crab Research

Terrestrial Hermit Crabs start life as microscopic, ocean-going larvae…and the story of how they change and wind up on shore – often many miles from where they started out, is still being unraveled. Please see the article linked below to read more about these fascinating creatures.

]]>http://blogs.thatpetplace.com/thatreptileblog/2014/02/10/best-substrate-hermit-crabs-avoid-deadly-mistakes/feed/62012’s New Species – Spiders, Roaches, Millipedes, Wasps – Which is your Favorite?http://blogs.thatpetplace.com/thatreptileblog/2013/01/03/2012s-new-species-spiders-roaches-millipedes-wasps-which-is-your-favorite/
http://blogs.thatpetplace.com/thatreptileblog/2013/01/03/2012s-new-species-spiders-roaches-millipedes-wasps-which-is-your-favorite/#commentsThu, 03 Jan 2013 19:35:36 +0000http://blogs.thatpetplace.com/thatreptileblog/?p=2752Invertebrate enthusiasts have learned to expect the discovery of fantastic new species on a regular basis. But even old timers such as I were shocked by some that came to light this past year. Large, claw-bearing Cave Robber Spiders, giant bio-luminescent roaches, brilliant arboreal tarantulas, neon-colored freshwater crabs, dive-bombing wasps…the list boggles the mind. Today ...

Invertebrate enthusiasts have learned to expect the discovery of fantastic new species on a regular basis. But even old timers such as I were shocked by some that came to light this past year. Large, claw-bearing Cave Robber Spiders, giant bio-luminescent roaches, brilliant arboreal tarantulas, neon-colored freshwater crabs, dive-bombing wasps…the list boggles the mind. Today I’ll highlight a few that have entranced me; please post your own favorites (whether covered here or not) below.

Cave Robber Spider, Trogloraptor marchingtoni

The Cave Robber Spider, arguably 2012’s most “otherworldly” discovery, turned up in a place not known for hiding unseen species – southwestern Oregon. In fact, not a single new spider has been described in the USA in the past 130 years.

Surprisingly, the Cave Robber is not a tiny, non-descript creature likely to be missed by all but the most passionate (“obsessed”?) of arachnologists. Rather, its legs span 3 inches, the pedipalps sport bulbous, fang-like projections, and it has 8 sharp, hooked claws that have been seen on no other of the world’s other 40,000+ spiders (please see photo). Furthermore, Cave Robbers have now also been found outside of caves, in several Oregon and California old growth forests. How could such a beast have been missed!?

Possibly related to the primitive Goblin Spiders, the Cave Robber is so unique that a new family, Trogloraptoridae, has been created for it. Little is known of its natural history and, unfortunately, captives have so far refused to feed.

Dive Bombing Wasp, Kallasoma sentum

Another of my favorites also hails from a country not known as an unseen species hotspot. Discovered in Spain, the minute Dive Bombing Wasp buzzes about just above “ant head level”, looking for a victim. Upon finding a target, the wasp swoops and, in 0.052 seconds, deposits a single egg on the ant. Its larvae later use the ant as a mobile meal. Ants try to repel the airborne attacks but, as you can see from this spectacular video, they are rarely successful.

The tiny wasp’s apparent reliance on a single ant species, and habitat loss, threaten its future.

Arachnologists suspect that Brazil’s Amazonian rainforests support many undiscovered tarantulas, but recently 9 new species were uncovered in the country’s semi-deciduous Atlantic Forests and Cerrado, a vast wooded savanna. These habitats were not expected to yield such an array of new spiders, all of which are boldly-marked and arboreal.

The new members of the genus Pachistopelma, the least-studied of all tarantula genera, seem to live only in plants known as Tank Bromeliads. There they ambush insects that are attracted to water that collects at the bromeliads’ bases. Among the newly-described species (genus Typhochaena) we also find the world’s smallest arboreal tarantulas. Please see the article below for natural history information and photographs.

Giant Glowing Roach, Lucihormetica luchae

This unusual insect was first described from a single specimen collected over 70 years ago. Glowing patches on the roach’s body lead predators to confuse with a toxic click beetle. While several roaches gain protection by mimicking noxious beetles (i.e. the popularly-kept Domino Roach) no others, and indeed no other terrestrial animals, do so via bioluminescence.

Unfortunately, the Giant Glowing Roach may already be extinct. It’s only known habitat was leveled when Ecuador’s Tungurahua Volcano exploded in 2010, and it has not been seen since.

Wandering Leg Sausage Millipede, Crurifarcimen vagans

The creature with this fanciful name hails from Tanzania’s Usambura Mountains, a region well known to tarantula enthusiasts and “new species hunters”. Although at 7 inches long this millipede is not the world’s largest, a very stout body and rusty-orange color renders it a most impressive beast (please see article below). Africa’s newest millipede dwells in decaying logs and has been found at 5,000+ feet above sea level.

Palawan Purple Crab, Insulamon palawanense

Freshwater crabs represent a huge evolutionary leap, and have very unusual lifestyles. I’ve kept several species, but interest in zoos and the pet trade is not high. This year, however, the discovery of 4 stunningly-beautiful freshwater crabs has drawn some attention to the group. All were found on Palawan, a Philippine island where over 50% of the resident species are endemic. Clad in “screaming” neon-violet and sporting red-tipped claws, the Palawan Purple Crab is a sight to behold…don’t miss its photo in the article below!

Palawan’s unique freshwater prawns are slated for further study as well.

Other Recently-Discovered Insects and Spiders

A number of other fascinating creatures have made invertebrate headlines in the recent past. Perhaps most incredible is the huge, semi-aquatic, flesh-eating Venezuelan Cave Cricket, Hydrolutos breweri. Found 2 miles into Cueva Charles Brewer, it has been described as swimming by using the front legs in breast-stroke fashion, and its jaws would give pause to even the most dedicated insect collector! One-of-a-kind footage of this astonishing creature in its natural habitat is provided by this video.

Other interesting new finds include a grasshopper-like cockroach and an ant-mimicking jumping spider with enormous fangs.

]]>http://blogs.thatpetplace.com/thatreptileblog/2013/01/03/2012s-new-species-spiders-roaches-millipedes-wasps-which-is-your-favorite/feed/2Hermit Crab Pets: The Coconut Crab & Other Specieshttp://blogs.thatpetplace.com/thatreptileblog/2012/11/07/land-hermit-crabs-and-coconut-crabs-the-worlds-largest-as-pets/
http://blogs.thatpetplace.com/thatreptileblog/2012/11/07/land-hermit-crabs-and-coconut-crabs-the-worlds-largest-as-pets/#commentsWed, 07 Nov 2012 14:45:59 +0000http://blogs.thatpetplace.com/thatreptileblog/?p=2671People are often surprised to learn that Land or Terrestrial Hermit Crabs engage in complex social behaviors, are capable of communicating via “chirps” and, with proper care, may live for over 20 years. I’ve had the pleasure of working with them at home, in zoos and the wild, and have even kept the massive, awe-inspiring ...

]]>People are often surprised to learn that Land or Terrestrial Hermit Crabs engage in complex social behaviors, are capable of communicating via “chirps” and, with proper care, may live for over 20 years. I’ve had the pleasure of working with them at home, in zoos and the wild, and have even kept the massive, awe-inspiring Coconut Crab. Please read on to learn about their care and natural history, and be sure to post your own thoughts and experiences.

Hermit Crab Natural History

The Purple-Pincher or Caribbean Hermit Crab (Coenobita clypeatus) is the most common pet trade species. It ranges throughout the Caribbean, reaching as far north as Florida and Bermuda.

Some populations live at altitudes of over 3,000 feet, but females return to the sea, usually in one massive migration, to spawn. The larvae, or zoea, float about with plankton for 2 months, after which they take up life on land.

Land Hermit Crabs carry about the discarded shells of other creatures as shelters, and must find larger shells as they grow. Recently it was discovered that they will line up in size order behind an empty shell – as the first crab (the largest) moves into its new home, others in line will “trade up” for the shell of the crab immediately in front of them! Please see the article below for details.

Ecuadorian Hermit Crabs (Coenobita compressus) and several Asian species also appear in the pet trade. The Coconut Crab (Birgus latro) is sometimes kept within its native range.

Crab Behavior

Land Hermit Crabs are nocturnal, but pets often emerge to feed by day. When established in a properly-designed terrarium, they will be quite active and exhibit many interesting behaviors.

Handling is stressful to Hermit Crabs, including long-term pets. They can be grasped by the back of the shell, but often can reach this area with their claw. Large individuals can administer a painful pinch, and I’d bet that the Coconut Crab can break fingers!

Housing

Setting up the Terrarium

A 10 gallon aquarium will accommodate 4-5 small crabs. Large, naturalistic terrariums will allow the crabs to exhibit a wider range of behaviors than will small, bare enclosures.

A molting tank should be set up if you keep more than one crab. Land Hermit Crabs are soft and defenseless after molting, and will be eaten by their former friends. Check daily for signs of an impending molt – digging, remaining below ground and listlessness are typical. Molting crabs should be isolated (please write in for information).

Substrate

A mix of calcium sand and coconut husk makes an ideal substrate. The substrate should be at least 6 inches deep and mixed with enough water so that is just sticks together when squeezed.

Land Hermit Crabs possess unique gills that enable them to breathe air. A humidity level of 70-80% is vital to survival, as the gills must be kept moist in order to function. A simple humidity meter should be used. Humidity can be increased by misting, adding water to the substrate and partially covering the terrarium’s lid with plastic.

Companions

Land Hermit Crabs are social animals, but dominant individuals may prevent others from feeding properly. Crabs that are molting must be isolated or they will be attacked (please see above). A variety of empty shells must be available, or fighting and “evictions” will ensue.

Feeding

Wild Hermit Crabs eat just about everything – animal, vegetable and mineral – that they encounter. Captives will not thrive without a varied, high-calcium diet.

Commercial Hermit Crab pellets may be used as a portion of the diet. The following foods should be included regularly: fresh shrimp and fish, fruits and vegetables (carrot may help to maintain coloration), hard-boiled egg, nuts, seeds, dry seaweed (sold as Nori), oatmeal, fish flakes, canned crickets, and freeze-dried fish foods (krill, plankton, brine shrimp, etc.). They also relish decaying wood and leaf litter; these should be collected from pesticide-free areas.

Often overlooked is their need for a bowl of marine water; marine aquarium salt mixes, not table salt, should be used. Soaking in this water will provide the crabs with essential minerals not present in their food. Fresh de-chlorinated water should also be available. Bowls should be filled to half the height of the smallest crab and be easily-exited, as Land Hermit Crabs drown easily.

A wide variety of specialty cages, supplies and foods are now available. Please post any questions or comments you may have regarding their use.

The Coconut Crab (Birgus latro), aka The Robber Crab

With a 16 inch body supported by legs spanning 3 feet, this impressive beast (described as “monstrous” by Charles Darwin!) is the world’s largest land-dwelling arthropod. I first saw them at the Cincinnati Zoo Insectarium in the early 1980’s, and was instantly hooked. After a prolonged search, I obtained 2 adults for an exhibit at the Bronx Zoo. Unfortunately, they did not fare very well, and this seems to be a common experience (wild individuals may attain age 40+). Losses are especially high during the month-long molt, which is spent underground.

The Coconut Crab ranges throughout the Indian and Western Pacific Oceans. A co-worker of mine found them raiding his garbage cans on Guam; his experiences with refuse-feeding coatis and coyotes elsewhere in no way prepared him for that!

Coconuts may be their best-known food, but form only a small portion of the diet. Generally, the crabs pinch nuts from coconut palms, and then feast on the broken remains below. A crab may also pull back the husk from an unbroken coconut and then pierce the soft “eye” with one of its pointed legs. The rest of the diet is as varied as that of their smaller relatives.

Coconut Crabs are declining in portions of their range. Threatened by food trade collection and predation by introduced rats, ants, pigs and monkeys, they have been extirpated from Australia and Madagascar.